1. Field of the Invention
The present invention relates generally to a power grinder, and more particularly to an installation/uninstallation structure for tooling disk of a grinder or a sander.
2. Description of the Related Art
A conventional electric or pneumatic grinder includes a grinding wheel/grinding disk mounted on a rotary shaft for grinding a work piece. The grinding wheel is a consumable product and needs to be replaced frequently.
In the conventional grinder, the grinding wheel is fixed at a rear end of the rotary shaft by a nut. When installing/uninstalling the grinding wheel, it is necessary to use one hand tool for holding the rotary shaft and another hand tool for screwing/unscrewing the nut. Therefore, the replacement of the grinding wheel necessitates two hand tools and is quite inconvenient.
Many improved installation/uninstallation structures are disclosed by the inventor in, for example, U.S. Pat. No. 7,014,548, U.S. Pat. No. 7,179,156, U.S. Pat. No. 7,128,641, U.S. Pat. No. 6,887,141, etc. In the improved installation/uninstallation structure, an engaging means is disposed in the grinding tool for locking the rotary shaft and hindering the rotary shaft from rotating. In this case, the grinding wheel can be installed/uninstalled with only one hand tool.
In such improved installation/uninstallation structure, the rotary shaft can be locked with the engaging means so that an operator can more conveniently replace the grinding wheel. However, the operator still needs to use one hand tool for screwing/unscrewing the screw member. In this case, it still takes some time to complete the replacement of the grinding wheel.
Moreover, the engaging means is mounted in the body of the grinding tool and has a complicated structure. In addition, it is hard to assemble the engaging means so that the manufacturing cost is increased.